Yes I had to hack the inner shape to get it out of the inner mold. It did have nice smooth inner sides which was why I went to so much trouble. It is clean and light as it appears in Pic1

Pics 2 and 3 were way too many hours fitting the thing under my pilot seat. It is not easy to get to and I was very careful to get a good fit. This took forever. At first I seemed to be squashing the tube a bit and had to bite the bullet and sink it into the floor a little. This was required the length of the tube and then into the rear seat area.

A lot of little details were still forming in my mind and in discussion with others. Just how to do all the things needed for this system.

A nice clean duct

A challenging fit

Under the front seat